WO2014012646A1

WO2014012646A1 - Internal combustion engine for a motor vehicle

Info

Publication number: WO2014012646A1
Application number: PCT/EP2013/002087
Authority: WO
Inventors: Klaus Rössler
Original assignee: Daimler Ag
Priority date: 2012-07-17
Filing date: 2013-07-13
Publication date: 2014-01-23
Also published as: DE102012014112A1

Abstract

The invention relates to an internal combustion engine (10) for a motor vehicle which can be operated with at least one gaseous fuel and has at least two combustion chambers (14), having a gas supply device (16), which comprises at least one reservoir (28) for storing the gaseous fuel, injector elements (18) assigned to each of the combustion chambers (14), which injector elements at least indirectly inject the gaseous fuel into the combustion chambers (14), and a distribution element (22) fluidically connected to the reservoir (28) and the injector elements (18) and common to the injector elements (18), by means of which distribution element the gaseous fuel supplied to the distribution element (22) can be distributed to the respective injector elements (18), wherein at least one valve element (46) is provided which is arranged in a corresponding line element (24) for supplying the gaseous fuel from the distribution element (22) to at least one of the injector elements (18) and by means of which the corresponding line element (24) can be shut off to fluids.

Description

Internal combustion engine for a motor vehicle

The invention relates to an internal combustion engine for a motor vehicle specified in the preamble of claim 1. Art.

Such an internal combustion engine for a motor vehicle is to be taken as known from US 5,745,210. The internal combustion engine can be operated with at least one gaseous fuel and has at least two combustion chambers. A gas supply device is provided which comprises at least one storage device for storing the gaseous fuel. The gas supply device also includes injector elements associated with the combustion chambers for the at least indirect introduction of the gaseous fuel into the combustion chambers. In addition, the gas supply device comprises a common to the injector elements, with the storage device and with the injector elements fluidly connected

Distribution element, by means of which the distribution element supplied gaseous fuel can be distributed to the respective injector elements.

After switching off the internal combustion engine, the gas supply device is initially under pressure. Leaks at the injector lead after switching off the internal combustion engine to an emptying of the

Gas supply device, in particular of the distribution element, the injector elements and corresponding line elements for guiding the gaseous fuel into the combustion chambers. This can lead to undesirably high unburned emissions

Hydrocarbons (HC) lead the gaseous fuel. In addition, it may come to startup problems of the internal combustion engine due to the leaks.

Discharging the gaseous fuel to the environment is not advantageous for environmental and safety reasons, as it thereby to the emission of unburned Hydrocarbons would come. A return of the gaseous fuel into the storage device and a discharge of the gaseous fuel in a separate container to reduce the gas pressure in the gas supply device after switching off the internal combustion engine, is technically complex and requires additional, large space.

It is therefore an object of the present invention, an internal combustion engine for a motor vehicle of the type mentioned in such a way that the above-mentioned problems after stopping the internal combustion engine can be avoided in a simple and space-saving manner or at least kept low.

This object is achieved by an internal combustion engine for a motor vehicle, in particular a passenger car, having the features of patent claim 1. Advantageous embodiments with appropriate and non-trivial

Further developments of the invention are specified in the remaining claims.

In order to provide an internal combustion engine for a motor vehicle specified in the preamble of claim 1 species, in which the described and resulting from the leaks of the injector disadvantages can be avoided in a simple and space-saving way or kept very low, at least one valve element is provided according to the invention in one

Corresponding conduit element for guiding the gaseous fuel from the distribution element to at least one of the injector elements is arranged and by means of which the corresponding conduit element is fluidically blocked. In other words, the valve element is in the flow direction of the gaseous fuel from the distribution element to the at least one injector downstream of the

Distribution element and upstream of the at least one injector arranged at least partially in the conduit element.

As a result, a gas volume, which can be emptied in the event of a leakage of the injector elements into the combustion chamber or the combustion chambers, can be kept particularly low. As a result, the emission of unburned hydrocarbons, especially methane, can also be avoided or kept to a minimum. In addition, a particularly advantageous starting behavior of

Internal combustion engine in time after their shutdown or after their deactivation allows. Furthermore, deflagrations in an intake tract and / or in an exhaust tract of the internal combustion engine can be avoided.

By appropriate arrangement of the at least one valve element in the corresponding line element particularly close to the corresponding

Injector limited to the gas volume, which can flow into the combustion chamber after stopping the internal combustion engine, at least in

Substantially to a corresponding receiving volume of the injector, in which the injector element can receive gaseous fuel. This very small volume of gas may be unburned in terms of emission

Hydrocarbons are considered to be uncritical on the influence of the starting behavior and on the influence of deflagrations in the intake and / or exhaust system.

In a further embodiment of the invention, the injector elements are each Uber at least one line element for guiding the gaseous fuel from

Distribution element fluidly connected to the respective injector element with the distribution element. In order to keep the after emptying of the internal combustion engine into the combustion chambers emptying gas volume is particularly low, is

advantageously in the respective conduit element, i. downstream of the

Distribution element and upstream of the respective injector elements at least one respective, corresponding valve element provided by means of which the respectively corresponding line element is fluidically blocked. In other words, in each of the line elements, via which the injector elements are connected to the distribution element, a corresponding valve element for fluidically blocking the corresponding line element is provided.

In a further embodiment of the invention, the valve element is as

electromagnetically actuated valve element formed. As a result, fast switching times of the valve element can be realized, so that the corresponding line element particularly fast at or after stopping the

Internal combustion engine can be fluidly blocked.

To realize a very good sealing effect of the corresponding valve element is provided in a further advantageous embodiment of the invention that the valve element at least one elastomer for fluidic locking of the

Includes line element. In a further embodiment of the invention, a control device is provided, which is designed to fluidly block the line element as a function of stopping the introduction of the gaseous fuel into the combustion chambers. In other words, a method of operating the

Internal combustion engine provided, wherein the conduit element is fluidly blocked in response to the termination of the introduction of the gaseous fuel into the combustion chambers. This can be used to turn off or deactivate the

Combustion engine can be reacted to the amount or volume of gaseous fuel flowing into the combustion chambers after deactivating the

To keep the internal combustion engine particularly low.

It is preferably provided that the control device is designed to fluidly block the line element in an automatic and / or in a caused by a person by deactivating the internal combustion engine finishing the introduction of the fuel into the combustion chambers. The automatic termination of the introduction of the fuel into the combustion chambers is carried out, for example, in the context of a so-called start / stop method in which the

Internal combustion engine upon fulfillment of at least one predetermined criterion automatically, i. without intervention of the driver of the motor vehicle, is deactivated. Such an automatic deactivation occurs, for example, when the driver stops the motor vehicle at a red traffic light and the motor vehicle no longer has to be driven or driven by the internal combustion engine.

For automatically terminating the introduction of the fuel into the combustion chambers, it may also occur during an overrun operation of the internal combustion engine, in which the internal combustion engine does not run through in the combustion chambers

Combustion processes, but is driven by the internal combustion engine in a Zugbebtrieb drivable wheels of the motor vehicle by its kinetic energy. In both cases, i. both during the start / stop process and during the overrun operation, in order to save fuel, no fuel is introduced into the combustion chambers and no burns are performed in the combustion chambers. In order now to the emptying into the combustion chambers gas volume and the resulting disadvantages, especially at a restart of the

To avoid internal combustion engine or keep low, the corresponding line element is fluidly blocked by means of the corresponding valve element. In a further embodiment of the invention, the internal combustion engine is operable in a first operating state with the gaseous fuel and in a second operating state with a liquid fuel. It is thus a bivalent combustion engine. This is for example a

Fuel supply device provided which comprises at least one tank for storing the liquid fuel and corresponding fuel injection valves for at least indirectly introducing the liquid fuel into the combustion chambers.

In order to keep the emptying gas volume particularly low, it is provided that the line element of the gas supply device is fluidly blocked in the second operating state by means of the valve element.

In a further advantageous embodiment of the invention, the storage device is fluidically connected via at least one further line element with the distribution element, wherein in the flow direction of the gaseous fuel from the

Storage device for distributing element in the further line element at least one further valve element is provided, by means of which the further line element is fluidly blocked, even if the first line element is fluidly blocked by means of the first valve element. In other words, the circuit of the first valve element with the at least one, further valve element, so that a particularly high density of the gas supply device is realized.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features mentioned above in the description and

Feature combinations as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone, without departing from the scope of the invention.

The drawing shows in the single FIGURE is a schematic representation of a

Internal combustion engine of a motor vehicle, which is operable with a gaseous fuel and a gas supply device for supplying the

Internal combustion engine having the gaseous fuel, wherein

Valve elements are provided, by means of which after deactivating the

Internal combustion engine in combustion chambers of this emptying gas volume can be kept particularly low. FIG. 1 shows an internal combustion engine 10 for a motor vehicle. The

Internal combustion engine 10 is operable with a gaseous fuel and comprises a crankcase 12, which has a plurality of cylinders 14 as combustion chambers of the internal combustion engine 10. The internal combustion engine 10 also includes an intake tract 15, via which air is drawn in and supplied to the cylinders 14.

The internal combustion engine 10 further has a gas supply device 16 for supplying the internal combustion engine 10 with the gaseous fuel. The gas supply device 16 comprises injectors 18, by means of which the gaseous fuel can be introduced directly into the cylinders 14, i. is inflatable. In other words, each of the cylinders 14 is associated with a respective injector 18, with a volumetric flow of the gaseous fuel flowing from the injectors 18 directly into the respective cylinders 14, i. without flowing through the intake tract 15, passes. Thus, the gaseous fuel is introduced directly into the cylinders 14 rather than upstream into the intake manifold 15, i. blown. In the intake tract 15, a throttle valve 20 is arranged, by means of which an amount of air to be supplied to the cylinders 14 is adjustable. In

Dependence on the cylinders 14 supplied amount of air is also the

Cylinders 14 supplied amount of gaseous fuel set.

The gas supply device 16 also includes a distribution element 22, which is also commonly referred to as a gas distributor. The distribution element 22 is fluidly connected via respective line elements 24 with the injectors 18. As a result, gaseous fuel can be supplied to the injectors 18 via the line elements 24 from the distribution element 22 common to the injectors 18.

The distribution element 22 is connected via a further line element 26 fluidly connected to a gas tank 28 of the gas supply device 16, so that the

Distribution element 22 via the further line element 26 gaseous fuel from the gas tank 28 can be supplied. In the further line element 26, a pressure regulator 30 is arranged, which comprises, for example, a valve element. By means of the pressure regulator 30, a pressure of the gaseous fuel in the distribution element 22 can be adjusted, with which the gaseous fuel is distributed from the distribution element 22 via the line elements 24 to the respective injectors 18. By means of the gas supply device 16, the gaseous fuel is injected into the cylinder 14, which is why the gas supply device 16 is also referred to as Einblaseeinrichtung. The internal combustion engine 10 further comprises an exhaust tract 32, by means of which exhaust gas of the internal combustion engine 10, which results from combustion of a fuel-air mixture in the cylinders 14, is discharged.

In order to operate the internal combustion engine 10 particularly efficiently, an exhaust gas turbocharger 34 is also provided. The exhaust-gas turbocharger 34 comprises a compressor 36 with a compressor wheel 38 arranged in the intake tract 15. By means of the compressor wheel 38, the air to be supplied to the internal combustion engine 10 can be compressed.

For driving the compressor wheel 38, the exhaust gas turbocharger 34 comprises a turbine 40 with a turbine wheel 42 arranged in the exhaust tract 32. The turbine wheel 42 can be driven by the exhaust gas and coupled to the compressor wheel 38 via a shaft 44 of the exhaust gas turbocharger 34. In the flow direction of the exhaust gas through the exhaust tract 32 downstream of the turbine wheel 42, an exhaust gas aftertreatment device 45 is arranged, which comprises, for example, a catalyst.

After turning off the internal combustion engine 10, i. after deactivating the

Internal combustion engine 10, the gas supply device 16 is initially under pressure. Leaks at the injectors 18 lead after stopping the

Internal combustion engine 10 for emptying the gas supply device 16 in the cylinder 14 and optionally in the intake manifold 15, if no appropriate countermeasures are taken. In this case, the gaseous fuel flows upstream of the cylinders 14, for example from the line elements 24, 26 and the injectors 18, into the cylinders 14. Particularly in the case of direct introduction or direct injection of the gaseous fuel, as provided in the internal combustion engine 10, a relatively high gas leakage may occur, since here a seal

In particular, the injectors 18 with elastomers due to high component temperatures is not possible. The elastomers would be thermally destroyed.

In order to prevent an undesirable high gas volume from flowing into the cylinders 14 after the internal combustion engine 10 has stopped, a respective, corresponding valve element 46 is arranged in the respective conduit element 24, by means of which the respective corresponding conduit element 24 can be fluidically blocked. In other words, in the line elements 24, respective valve elements 46 are provided for fluidically blocking the line elements 24, which in FIG

Flow direction of the gaseous fuel from the distribution element 22 to the respective injectors 18 are arranged between the distribution element 22 and the injectors 18.

The valve elements 46 are magnetically actuated, which is why they are also referred to as solenoid valves. The valve elements 46 are by means of an electronic

Control unit 48 of the internal combustion engine 10 between a line member 24 fluidly blocking the blocking position and the conduit elements 24 at least partially fluidly releasing release position adjusted.

If the internal combustion engine 10 is deactivated, the valve elements 46 are adjusted in their respective blocking positions. As a result, due to the leaks in the injectors 18, only the emptying of a very small gas volume occurs, which is limited to a respective receiving volume of the injectors 18, in which gaseous fuel can be received. This small volume of gas can with regard to the emission of unburned hydrocarbons (HC), in particular of

unburned methane, as well as an impact on a starting behavior of the internal combustion engine 10 and deflagration in the intake tract 15 and the exhaust tract 32 are considered to be uncritical.

Any gaseous fuel taken up in the distribution element 22 when deactivating the internal combustion engine 10, and also further upstream in the

Line member 26 and received in the gas tank 28 fuel can not flow through the leaks of the injectors 18 in the cylinder 14, as such

Flow path is fluidly blocked by means of the valve elements 46 located in the blocking position.

During the subsequent starting of the internal combustion engine 10, the additional valve elements 46 are switched back into their respective release positions by means of the control device 48 and thereby opened, so that the gaseous fuel can again flow from the gas tank 28 to the injectors 18 and into the cylinders 14.

In order to realize a particularly high sealing effect of the valve elements 46, they can each comprise at least one elastomer for fluidically blocking the respective line element 24. The use of such an elastomer is possible because the valve elements 46 are substantially smaller

Temperature stress subject to the injectors 18, so that the respective elastomer is not thermally or very little claimed. So can one unwanted, thermal destruction of the elastomers are avoided, so that they can close the line elements 24 tight over a very long life.

Claims

claims

An internal combustion engine (10) for a motor vehicle, which is operable with at least one gaseous fuel and at least two combustion chambers (1), with a gas supply device (16), which at least one storage device (28) for storing the gaseous fuel, respectively Combustion chambers (14) associated injector elements (18) for at least indirectly introducing the gaseous fuel into the combustion chambers (14) and the injector elements (18) common, with the memory device (28) and with the injector elements (18) fluidly connected distribution element (22) comprising, by means of which the gaseous fuel supplied to the distribution element (22) can be distributed to the respective injector elements (18),

characterized in that

at least one valve element (46) is provided, which in a

corresponding conduit element (24) for guiding the gaseous fuel from the distribution element (22) to at least one of the injector elements (18) is arranged and by means of which the corresponding conduit element (24) is fluidically blocked.

2. internal combustion engine (10) according to claim 1,

characterized in that

the injector elements (18) are each fluidically connected to the distribution element (22) via at least one line element (24) for guiding the gaseous fuel from the distribution element (22) to the respective injector element (18), at least one in the respective line element (24) respective, corresponding valve element (46) is provided, by means of which the respectively corresponding line element (24) is fluidically lockable.

3. internal combustion engine (10) according to any one of claims 1 or 2,

characterized in that

the valve element (46) is designed as an electromagnetically operable valve element (46).

4. internal combustion engine (10) according to one of the preceding claims, characterized in that

the valve element (46) comprises at least one elastomer for fluidically blocking the line element (24).

5. internal combustion engine (10) according to one of the preceding claims, characterized in that

a control device (48) is provided, which is designed to fluidly block the line element (24) in response to an end of the introduction of the gaseous fuel into the combustion chambers (14) by means of the valve element (46).

6. internal combustion engine (10) according to claim 5,

characterized in that

the control device (48) is designed to enable the line element (24) to be automatically and / or stopped by a person by deactivating the internal combustion engine (12)

Fuel in the combustion chambers (14) by means of the valve element (46) to block fluidly.

7. internal combustion engine (10) according to one of the preceding claims, characterized in that

the internal combustion engine (12) is operable in a first operating state with the gaseous fuel and in a second operating state with a liquid fuel, wherein the conduit element (24) in the second

Operating state by means of the valve element (46) is fluidly blocked.

8. Internal combustion engine (10) according to one of the preceding claims, characterized in that

the storage device (28) is fluidically connected to the distribution element (22) via at least one further line element (26), wherein in the flow direction of the gaseous fuel from the storage device (28) to

Distribution element (22) in the further line element (26) at least one further valve element between the distribution element (22) and the

Memory device (28) is provided, by means of which the further

Conduit element (26) is fluidly blocked, although the first conduit member (24) by means of the first valve element (46) is fluidly blocked.

9. motor vehicles with an internal combustion engine (10) according to one of

previous claims.